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3.
INTRODUCTION
• The Project is all about the protecting transformer under
overload condition.
• Drop in efficiency and overheating in secondary
winding can be prevented with the help of this project.
• Load sharing of the transformer is possible with the
help of this project theme and the life of the transformer
is increased.
• The project is also used as a Un-interrupted power
supply (UPS)
• If short circuit fault is occurs the transformer will get
protected.

5.
OBJECTIVES
• The main aim of the project is transformer sharing
whenever load is increased for certain value and also
sending this change in information to the respective
authority via SMS by using GSM modem
• The objective of this project is to protect the
Domestic supply and Power Transformers from over
load power.

7.
EXPLANATION OF BLOCK DIAGRAM
• TRANSFORMER
– two parallel transformers for sharing load
• RELAYS and RELAY DRIVER
– It is electrically operated switch
– It disconnect circuit when current flow becomes
greater than desired value
– Both relays are controlled by relay driver
• CURRENT TRANSFORMER
– It is a step down transformer
– divide current according to load

10.
EXPLANATION OF CIRCUIT DIAGRAM
• 230 v ac supply is step down using CT and PT
• Whole circuit operates on 5 v or 12v supply, this supply
provided by using bridge rectifier
• The output of CT and PT given to current and voltage
measurement circuit
• PIC microcontroller compares the output of both circuits with
reference value
• Reference value are given by using keypad to the
microcontroller
• Relay are operated by PIC microcontroller
• LCD displays the value of load

12.
POWER SUPPLY
• Whole circuitry work on +5v,+12v & -12v DC power
• Supply of 230v AC is applied to the transformer
• By using transformer, rectifier, filters, IC regulators
etc. we get the desired output

14.
DESCRIPTION OF POWER SUPPLY
• Transformer
– 230v AC is step down to 5v and 12v as per requirement of
circuitry
• Rectifier
– It converts the AC supply in to the pulsating DC supply
• Filters
– It removes the ripples from the DC supply which are coming
from the rectifier
• IC regulator
– IC regulator is providing the fixed DC voltage which load (i.e.
relays and PIC microcontroller) required

15.
TRANSFORMER
• An electrically isolated but magnetically coupled
device, which transformed electrical power from one
circuit to another circuit without changing frequency
is called TRANSFORMER
• It accomplishes this by electromagnetic induction

16.
TRANSFORMER Cont’d
• There are basically two types
– Step Down transformer
– Step Up transformer
• We are using step down transformer
• CT and PT are step down transformer

17.
RECTIFIER
• It is a circuit which converts AC to DC
• Output of a rectifier is not pure DC, it is pulsating DC
• There are basically two types of rectifier
– Half wave rectifier
– Full wave rectifier
• Bridge rectifier
• We are using Bridge rectifier to get desired DC output
voltage of +5v,+12v and -12v

19.
WORKING OF BRIDGE RECTIFIER
• At +ve half cycle there is +ve potential at node A and –ve
potential at node B
• Due to which D1 and D4 are in forward bias and D2 and
D3 are work in reverse bias, we get DC voltage of +ve
half cycle
• Similarly at -ve half cycle there is +ve potential at node B
and –ve potential at node A
• Due to which D2 and D3 are in forward bias and D1 and
D4 are work in reverse bias, we get DC voltage of -ve
half cycle
• When the operation of full wave bridge rectifier is
complete, we get output that is pulsating DC.

20.
FILTERS
• An element or device which removes unwanted
signals from the supply is called as filters
• Rectifier output is in the form of pulsating DC which
contain certain ripples
• To remove this ripples and to get pure DC supply
filters are used
• In Bridge rectifier capacitor works as filter which
removes AC ripple components from the rectifier
output

22.
IC REGULATOR Cont’d
• Regulator IC is the IC which provides the fixed
voltage to the different components even if the input
of the regulator IC is vary
• Regulator IC units contain the circuitry for reference
source, comparator amplifier, control device, and
overload protection all in a single IC
• In our project we are using 7805,7812,7912 IC
regulator

23.
PIC MICROCONTROLLER
• PIC stand for programmable interrupt controller
• PICs are popular for low cost, wide availability, large
user base, free development tools and serial
programming (and reprogramming with flash
memory) capability so we are using PIC
microcontroller
• PIC microcontroller is the first RISC base
microcontroller

25.
PIC MICROCONTROLLER
•Pin no 3-current measurement
•The output of current measurements are given to microcontroller through
this pin
•According to the measurement microcontroller giving the signal to
various component of the circuit
•Pin no 8,9,10,18,23-keypad
•Keypad is connected through the microcontroller via this pins
•The reference values of current and voltages through keypad to
microcontroller
•Pin no 1-reset
•The microcontrollers data is reset via this pins
•Pin no 12,31-gnd
•This pins are connected to the ground

26.
PIC MICROCONTROLLER Cont’d
• Pin no 13,14-crystal oscillator
• Crystal oscillator generates about 1200MHZ of frequency
which is called oscillating frequency
• Microcontroller works on oscillating frequency
• Pin no 33,34-realy circuit
• Relays are operated via this pins of microcontroller
• Pin no 19,20,21,22,27,28,29,30-LCD
• This pins of microcontroller are given to the LCD display
unit
• LCD display the load values
• Pin no 11,32-VCC
• Fixed voltage is given to the microcontroller via this pins

28.
VOLTAGE MEASUREMENT Cont’d
• Potential transformer(PT) is use to monitor the
supply voltage
• Supply voltage that has to be monitor is step
down by PT
• The step down voltage is rectified by bridge
rectifier
• Different DC voltage which required by relay and
PIC are to be given by using IC regulator
• The function of voltage measurement is to
provide step down voltage

30.
CURRENT MEASUREMENT Cont’d
• Current transformer(CT) is use to step down
current
• The circuit is design to monitor the supply
current
• The step down current is converted by voltage
with the help of shunt register

32.
RELAYS Cont’d
• It is an electromagnetic device which is use as switch
• it has a magnetic coil which is use to connect or
disconnect the transformer
• It is electrically operated switch
• It disconnect circuit when current flow becomes greater
than desired value
• Both relays are controlled by relay driver
• If the current consumption is above 50% then the lower
relay get switch OFF through the relay driver circuit.
• IF the current consumption is above 80% then the all
relay get switch OFF through the relay driver circuit.

36.
FUTURE SCOPE
• GSM-(global system for mobile
communication)
– GSM is globally accepted standard for digital
cellular communication
– Frequency range 900MHZ to 1990MHZ
– PIC microcontroller sends actual load value to the
authority via SMS by using GSM
– In our project we are using only transmitter to
transmit the data
– In our project we are not yet get the required
frequency GSM